CN104693337A - Synthetic method for tetrafluoroethylene-propylene copolymer crude rubber - Google Patents

Abstract

The invention discloses a synthesis method of tetrafluoroethylene-propylene copolymer raw rubber. Emulsion polymerization of tetrafluoroethylene and propylene monomers in water/tert-butanol mixed medium under the action of a new oxidation-reduction initiation system composed of peroxide initiator and NaCO ₂ CH(OH)SO ₂ Na reducing agent Tetrafluoroethylene-propylene copolymer latex is obtained, and the latex is demulsified and dried to obtain tetrafluoroethylene-propylene copolymer raw rubber. The present invention uses NaCO ₂ CH(OH)SO ₂ Na reducing agent to replace commonly used reducing agents such as sodium formaldehyde sulfoxylate, ferrous sulfate, etc., not only can maintain a high polymerization rate of tetrafluoroethylene-propylene copolymerization near room temperature, and obtain high Tetrafluoroethylene-propylene copolymer with high molecular weight, and no formaldehyde decomposition products and iron hydroxide precipitates are produced during the reaction process. The product is environmentally friendly and colorless. Further processing and cross-linking can obtain high-performance tetrafluoroethylene-propylene copolymer rubber.

Description

A kind of synthetic method of tetrafluoroethylene-propylene copolymer raw rubber

technical field

The invention relates to the technical field of chemical engineering, in particular to a method for synthesizing tetrafluoroethylene-propylene copolymer raw rubber.

Background technique

Tetrafluoroethylene-propylene copolymerization can form tetrafluoroethylene (TFE) and propylene (P) alternating structure, low glass transition temperature, good flexibility copolymer, further vulcanization (crosslinking) processing to obtain rubber products with excellent performance, Commonly known as tetrapropylene fluororubber. Compared with ethylene-propylene copolymer (ethylene-propylene) rubber, because the four hydrogen atoms in the ethylene unit are replaced by fluorine atoms, tetrapropanefluororubber has the characteristics of corrosion resistance, high temperature resistance, and high insulation of fluororubber. It can be used in Long-term use at 200°C, intermittent use at 230°C. The processing performance of tetrapropylene fluororubber is superior to other fluororubbers. It can be made into various O-rings, seals, diaphragms, gaskets, valve biases, hoses, rubber rollers, cables and other products by extrusion, molding and other molding processes. .

The Japan Institute of Atomic Energy was the first to use radiation to initiate low-temperature solution polymerization of TFE-P. DuPont applied for the first TFE-P emulsion copolymerization patent in 1969. Because only ammonium persulfate initiator was used, the polymerization temperature was high, the polymerization rate and copolymer molecular weight were low, and the pressure of the polymerization system was high. In order to obtain high molecular weight TFE-P copolymers, Japan Asahi Glass Co., Ltd. and the Japan Institute of Atomic Energy began to conduct research on radiation-induced low-temperature TFE-P emulsion copolymerization in the 1970s, using gamma-ray radiation generated by ⁶⁰ Co to initiate polymerization. However, due to the difficulty and danger of the operation caused by irradiation, there have been no reports of industrial implementation.

Subsequently, Asahi Glass Co., Ltd. began to develop the TFE-P emulsion copolymerization technology initiated by the oxidation-reduction initiation system. The oxidation-reduction initiation system reported in the company's patent is mainly composed of water-soluble persulfate and inorganic reducing agent. The reducing agent includes thio Sulfates, sulfites, formaldehyde sulfoxylate (US 4277586). In order to further increase the polymerization rate, more ferrous salts and ethylenediaminetetraacetic acid (EDTA) (US 4463144) were added to the polymerization system. For the polymerization system adding ferrous salt, maintaining the pH value of the system at weak alkaline (8.5~10) is beneficial to increase the polymerization rate. The papers published by Kojima et al. (Makromol. Chem., 1981, 182: 1429-1439) of Asahi Glass Company reported the concentration of ammonium persulfate initiator, ferrous sulfate concentration, sodium formaldehyde sulfoxylate concentration, ammonium perfluorooctanoate concentration, polymerization temperature, system The effect of pH value, tert-butanol content, etc. on the polymerization rate of TFE-P and the average molecular weight of the copolymer, it was found that the initiator concentration had little effect on the polymerization rate and the molecular weight of the copolymer within a certain range, but with ferrous sulfate and formaldehyde When the concentration of sodium sulfate reducing agent increases, the polymerization rate increases gradually, but the molecular weight of the copolymer does not change much; when the concentration of emulsifier increases, the polymerization rate and the molecular weight of the copolymer both increase. In addition, it was found that when the pH value of the system increased from 5 to about 9, the polymerization rate continued to increase significantly. When the pH value was 9-10.5, the polymerization rate remained at the highest level, and when the pH value continued to increase, the polymerization rate decreased rapidly.

In the 1990s, based on the study of TFE-P bulk copolymerization initiated by tert-butyl peroxybenzoate (TBPB), Petrov et al. studied the oxidation-reduction system of TBPB-FeSO ₄ –CH ₂ (OH)SO ₂ Na-EDTA Initiated TFE-P emulsion copolymerization was studied (J. Polym. Sci,: Polym. Chem., 1994, 32: 2229~2234, 2235~2239), and found that the initiation system can also realize TFE-P at room temperature ( 25℃) polymerization, with the increase of TBPB concentration, the polymerization rate and the molecular weight of the copolymer do not change much, but with the increase of the concentration of ferrous sulfate and sodium formaldehyde sulfoxylate, the polymerization rate increases, and the molecular weight of the copolymer decreases slightly; As the concentration of ammonium perfluorooctanoate emulsifier increases, the polymerization rate increases, and the molecular weight of the copolymer first increases and then tends to balance. Using organic peroxide initiator can improve the thermal stability of TFE-P copolymer to a certain extent.

It can be seen that in order to obtain high molecular weight TFE-P copolymer raw rubber, the polymerization temperature cannot be too high, so patents and literature reports often use oxidation-reduction initiation systems to initiate polymerization to obtain higher polymerization rates. However, most oxidation-reduction initiation systems contain sodium formaldehyde sulfoxylate and/or ferrous salt. Sodium formaldehyde sulfoxylate will decompose and produce formaldehyde during polymerization or post-drying treatment, which will be released into the environment or contained in raw rubber, affecting the sanitation of products. Sex, it is difficult to meet the use requirements of high-end products. Ferrous ions are oxidized to generate ferric ions, and under alkaline conditions, a dark precipitate of ferric hydroxide will be formed, which is contained in TFE-P copolymer emulsion and raw rubber, which will make the product colorful.

For above problem, the present invention proposes a kind of method that the initiation system that is made up of organic peroxide and novel reductant initiates the method for TFE-P emulsion copolymerization, and the molecular formula of reductant is NaCO ₂ CH(OH)SO ₂ Na, by German Bruggenemann Developed and patented by Chemical Company, the brand is Bruggolite FF6M. After the combination of the reducing agent and the peroxide initiator, it has a faster initiation rate than the combination of the same initiator and sodium formaldehyde sulfoxylate, and is suitable for polymerization in a wide pH range. The reaction process does not generate formaldehyde, which can reduce the generation of volatile organic compounds (VOC), and is an environmentally friendly reducing agent. Using the oxidation-reduction initiation system of the present invention to carry out TFE-P emulsion copolymerization can realize rapid emulsion polymerization of TFE-P under the conditions of simplifying the composition of the oxidation-reduction system, reducing the amount of initiator and VOC generation, and obtaining high-molecular-weight, high-quality TFE-P copolymer raw rubber.

Contents of the invention

The object of the present invention is to provide a kind of synthetic method of tetrafluoroethylene-propylene copolymer raw rubber.

A synthetic method of tetrafluoroethylene-propylene copolymer raw rubber is: add 1000 grams of deionized water, 20-100 grams of tert-butanol, 1.5-5.0 grams of perfluorooctanoic acid ammonium, and 0.5-2.5 grams of peroxide initiator into high-pressure reaction In the kettle, after sealing and filling with nitrogen and exhausting oxygen, stir and raise the temperature to 20~40 ^o C, add NaCO ₂ CH(OH)SO ₂ Na aqueous solution with a molar ratio of 2/1~1/2 to the initiator once or continuously into the kettle At the same time, pump the initial tetrafluoroethylene/propylene mixed monomer with a molar ratio of 80/20~70/30 into the kettle until the pressure in the kettle reaches the set value between 1.5~2.5MPa, and start polymerization. When the pressure in the kettle After a drop of 0.1MPa, pump in supplementary tetrafluoroethylene/propylene mixed monomer with a molar ratio of 60/40~50/50 until the pressure reaches the set value, and after the pressure drops again by 0.1MPa, pump in supplementary tetrafluoroethylene/propylene Propylene mixed monomer, repeat the above mixed monomer replenishment process, when the monomer replenishment reaches 20~30 times or the reducing agent is added dropwise, the mixed monomer replenishment is completed, and after polymerization until the pressure drops by 0.5MPa, the remaining monomer is removed. Finish the polymerization to obtain tetrafluoroethylene-propylene copolymer latex; add a coagulant to the tetrafluoroethylene-propylene copolymer latex to break the emulsion and coagulate the latex, and the coagulation is filtered, washed with deionized water, and dried to obtain tetrafluoroethylene-propylene copolymer latex. Biological raw rubber.

Described peroxide initiator is tert-butyl peroxybenzoate, tert-amyl peroxybenzoate, tert-butyl peroxyacetate, tert-amyl peroxyacetate, 3,5,5-trimethyl peroxide tert-butyl hexanoate, tert-amyl 3,5,5-trimethylhexanoate peroxide, tert-butyl peroxyisopropyl carbonate, tert-butyl peroxy 2-ethylhexyl carbonate or 2-ethyl peroxide tert-Amyl Hexyl Carbonate.

The coagulant is sodium chloride, calcium chloride, magnesium chloride, aluminum chloride, sodium sulfate or aluminum sulfate.

The present invention uses NaCO ₂ CH(OH)SO ₂ Na reducing agent to replace the reducing agents such as sodium formaldehyde sulfoxylate and ferrous sulfate commonly used in TFE-P emulsion copolymerization, which can not only maintain a high polymerization rate near room temperature, but also obtain high molecular weight TFE -P copolymer raw rubber, and there is no formaldehyde decomposition product and iron hydroxide precipitate in the reaction process, the product has good hygiene and small color, and can be processed to obtain high-performance TFE-P copolymer rubber.

Detailed ways

The synthesis of TFE-P copolymer is carried out by emulsion polymerization, and the reaction medium is mainly deionized water. At the same time, in order to improve the solubility of initiator and monomer, tert-butanol solvent which is miscible with water is properly added. Ammonium perfluorooctanoate is used as the emulsifier, which can protect the formed copolymer particles and obtain a stable emulsion. The dosage is 0.15-0.50% (relative to deionized water).

The peroxide initiator used is an oil-soluble organic peroxide initiator with a 10-hour half-life in benzene and a temperature of about 100 ^o C, including tert-butyl peroxybenzoate, tert-amyl peroxybenzoate, and tert-butyl peroxyacetic acid. Butyl ester, tert-amyl peroxyacetate, tert-butyl peroxy-3,5,5-trimethylhexanoate, tert-amyl peroxy-3,5,5-trimethylhexanoate, isopropyl peroxycarbonate tert-butyl peroxide, tert-butyl peroxy 2-ethylhexyl carbonate, tert-amyl peroxide 2-ethylhexyl carbonate, the dosage is 0.05~0.25% of the quality of deionized water.

In order to increase the decomposition rate of the initiator and meet the needs of TFE-P emulsion polymerization at room temperature, a new reducing agent NaCO ₂ CH(OH)SO ₂ Na is added. The reducing agent is water-soluble and can be used as an aqueous solution once after the reactor is sealed and exhausted. Or continuous addition. Generally, when the polymerization temperature is set low (such as 20~25 ^o C), the reducing agent can be added at one time, and when the polymerization temperature is set high (25~40 ^o C), the reducing agent can be added Join in a row. The molar ratio of reducing agent dosage to initiator dosage is 1/2~2/1.

In order to obtain TFE-P copolymer raw rubber with large molecular weight, the polymerization temperature is set at 20~40 ^o C. If the polymerization temperature is too high, the molecular weight of the obtained TFE-P copolymer is low, and the tensile strength and Resilience is low. If the polymerization temperature is too low, the polymerization reaction rate will decrease, and the amount of oxidation-reduction initiation system will be too large.

Both TFE and P are gas-phase monomers, which need to be injected into the polymerization kettle with a high-pressure pump after the start of polymerization. The molar ratio of TFE/P monomer added for the first time is between 80/20~70/30, which can be pre-mixed The two monomers are mixed according to the set molar ratio, and then the polymerization system is heated to the set temperature before being added to the polymerization tank. Add TFE/P mixed monomer for the first time until the pressure in the kettle reaches the initial set value between 1.5~2.5MPa. After the polymerization starts for a certain period of time, the pressure in the kettle drops. When the pressure drops by 0.1MPa (relative to the initial set value), Pump in supplementary TFE/P mixed monomer with a molar ratio of 60/40~50/50 until the pressure reaches the set value, and after the pressure drops again by 0.1MPa, pump in supplementary TFE/P mixed monomer, repeat the above mixing In the monomer replenishment process, when the monomer replenishment reaches 20~30 times or the reducing agent is added dropwise, the mixed monomer replenishment is completed, and the polymerization is continued until the pressure drops by 0.5MPa (relative to the initial set pressure value), and the unreacted monomer is removed. After the end of the polymerization, the TFE-P copolymer latex can be obtained.

Adding an inorganic salt coagulant to the TFE-P copolymer latex makes the latex demulsify and coagulate, and the coagulate is filtered, washed with deionized water, and dried to obtain tetrafluoroethylene-propylene copolymer raw rubber. The inorganic salt coagulant used is sodium chloride, magnesium chloride, calcium chloride, aluminum chloride, sodium sulfate, aluminum sulfate, and the amount of the coagulant added is based on the complete coagulation of the latex.

Example 1

Add 1000 grams of deionized water, 40 grams of tert-butanol, 2.0 grams of ammonium perfluorooctanoate, and 2.0 grams (0.0103 mol) of tert-butyl peroxybenzoate initiator into the autoclave. ^o C, add an aqueous solution containing 1.689 grams (0.0103mol) NaCO ₂ CH(OH)SO ₂ Na to the kettle at one time, pump the initial TFE/P mixed monomer with a molar ratio of 80/20 into the kettle to the pressure in the kettle When the pressure reaches 2.0MPa, start polymerization. When the pressure in the kettle drops by 0.1MPa, pump in supplementary TFE/P mixed monomer with a molar ratio of 60/40 until the pressure reaches 2.0MPa, and after the pressure drops again by 0.1MPa, pump in supplementary TFE/P mixed monomer, repeat the above mixed monomer replenishment process, when the monomer replenishment reaches 20 times, end the mixed monomer replenishment, polymerize until the pressure drops to 1.5MPa, remove the remaining monomer, end the polymerization, and obtain TFE- P copolymer latex; adding aluminum chloride to the copolymer latex to break the emulsion and coagulate, and the coagulation is filtered, washed with deionized water, and dried to obtain TFE-P copolymer raw rubber.

Example 2

Add 1000 grams of deionized water, 20 grams of tert-butanol, 2.5 grams of ammonium perfluorooctanoate, and 2.5 grams (0.0096 mol) of tert-amyl peroxide 2-ethylhexyl carbonate initiator into the autoclave, seal it, fill it with nitrogen and exhaust it, Stir and heat up to 20 ^o C, add an aqueous solution containing 3.15 grams (0.0192mol) NaCO ₂ CH(OH)SO ₂ Na to the kettle at one time, and pump the initial TFE/P mixed monomer with a molar ratio of 80/20 into the kettle When the pressure in the kettle reaches 2500KPa, start polymerization. When the pressure in the kettle drops by 0.1MPa, pump in the supplementary TFE/P mixed monomer with a molar ratio of 60/40 until the pressure reaches 2.5MPa, and after the pressure drops by 0.1MPa again, Pump in the replenishment of TFE/P mixed monomer, repeat the above mixed monomer replenishment process, when the monomer replenishment reaches 25 times, end the mixed monomer replenishment, polymerize until the pressure drops to 2.0KPa, remove the remaining monomer, and end the polymerization. TFE-P copolymer latex is obtained; sodium chloride is added to the copolymer latex to demulsify and coagulate, and the coagulated matter is filtered, washed with deionized water, and dried to obtain TFE-P copolymer raw rubber.

Example 3

Add 1000 grams of deionized water, 60 grams of tert-butanol, 1.5 grams of ammonium perfluorooctanoate, and 2.46 grams (0.010 mol) of 2-ethylhexyl peroxide tert-butyl carbonate initiator into the autoclave, and seal it with nitrogen and exhaust it. Stir and heat up to 25 ^o C, add an aqueous solution containing 1.64 g (0.010 mol) NaCO ₂ CH(OH)SO ₂ Na to the kettle at one time, and pump the initial TFE/P mixed monomer with a molar ratio of 70/30 into the kettle When the pressure in the kettle reaches 2.0MPa, start polymerization. When the pressure in the kettle drops by 0.1MPa, pump in the supplementary TFE/P mixed monomer with a molar ratio of 55/45 until the pressure reaches 2.0MPa, and after the pressure drops by 0.1MPa again , pump in supplementary TFE/P mixed monomer, repeat the above mixed monomer replenishment process, when the monomer replenishment reaches 20 times, end the mixed monomer supplement, polymerize until the pressure drops to 1.5MPa, remove the remaining monomer, and end the polymerization , to obtain TFE-P copolymer latex; adding calcium chloride to the copolymer latex to demulsify and coagulate, and the coagulation is filtered, washed with deionized water, and dried to obtain TFE-P copolymer raw rubber.

Example 4

Add 1000 grams of deionized water, 80 grams of tert-butanol, 2.0 grams of ammonium perfluorooctanoate, and 2.44 grams (0.010 mol) of tert-amyl peroxide 3,5,5-trimethylhexanoate initiator into the autoclave, seal and fill After nitrogen and oxygen removal, stir and heat up to 25 ^o C, add an aqueous solution containing 1.64 g (0.010 mol) NaCO ₂ CH(OH)SO ₂ Na to the kettle at one time, and pump initial TFE with a molar ratio of 80/20 into the kettle /P mixed monomer until the pressure in the kettle reaches 2.0MPa, start polymerization, when the pressure in the kettle drops by 0.1MPa, pump in the supplementary TFE/P mixed monomer with a molar ratio of 50/50 until the pressure reaches 2.0MPa, and After falling again by 0.1MPa, pump in the supplementary TFE/P mixed monomer, repeat the above mixed monomer replenishment process, when the monomer replenishment reaches 20 times, end the mixed monomer replenishment, polymerize until the pressure drops to 1.5MPa, and remove the remaining After the monomer is polymerized, TFE-P copolymer latex is obtained; magnesium chloride is added to the copolymer latex to demulsify and coagulate, and the aggregate is filtered, washed with deionized water, and dried to obtain TFE-P copolymer raw rubber.

Example 5

Add 1000 grams of deionized water, 100 grams of tert-butanol, 2.0 grams of ammonium perfluorooctanoate, and 2.30 grams (0.010 mol) of tert-butyl peroxide 3,5,5-trimethylhexanoate initiator into the autoclave, seal and fill After nitrogen and oxygen removal, stir and heat up to 25 ^o C, add an aqueous solution containing 1.64 g (0.010 mol) NaCO ₂ CH(OH)SO ₂ Na to the kettle at one time, and pump initial TFE with a molar ratio of 80/20 into the kettle /P mixed monomer until the pressure in the kettle reaches 2.0MPa, start polymerization, when the pressure in the kettle drops by 0.1MPa, pump in the supplementary TFE/P mixed monomer with a molar ratio of 55/45 until the pressure reaches 2.0MPa, and After another drop of 0.1MPa, pump in the supplementary TFE/P mixed monomer, repeat the above mixed monomer replenishment process, when the monomer replenishment reaches 25 times, end the mixed monomer replenishment, polymerize until the pressure drops to 1.5MPa, and remove the remaining The monomer is polymerized to obtain TFE-P copolymer latex; sodium sulfate is added to the copolymer latex to demulsify and coagulate, and the aggregate is filtered, washed with deionized water, and dried to obtain TFE-P copolymer raw rubber.

Example 6

Add 1,000 grams of deionized water, 40 grams of tert-butanol, 5.0 grams of ammonium perfluorooctanoate, and 1.0 grams (0.00756 mol) of tert-butyl peroxyacetate initiator into the autoclave, seal it, fill it with nitrogen and exhaust oxygen, and stir to raise the temperature to 35 ^o C. Continuously add an aqueous solution containing 2.48 grams (0.01513mol) of NaCO ₂ CH(OH)SO ₂ Na into the kettle, and pump the initial TFE/P mixed monomer with a molar ratio of 80/20 into the kettle until the pressure in the kettle reaches 2.0MPa, start polymerization, when the pressure in the tank drops by 0.1MPa, pump in supplementary TFE/P mixed monomer with a molar ratio of 55/45 until the pressure reaches 2.0MPa, and after the pressure drops again by 0.1MPa, pump in supplementary TFE /P mixed monomer, repeat the above mixed monomer replenishment process, when the reducing agent aqueous solution is pumped, stop the mixed monomer replenishment, polymerize until the pressure drops to 1.5MPa, remove the remaining monomer, and end the polymerization to obtain TFE-P Copolymer latex: Add aluminum sulfate to the copolymer latex to break the emulsion and coagulate, and the coagulate is filtered, washed with deionized water, and dried to obtain TFE-P copolymer raw rubber.

Example 7

Add 1000 grams of deionized water, 40 grams of tert-butanol, 2.0 grams of ammonium perfluorooctanoate, and 0.50 grams (0.00284 mol) of tert-butyl peroxyisopropyl carbonate initiator into the autoclave, seal it, fill it with nitrogen and exhaust oxygen, and stir to raise the temperature To 40 ^o C, continuously add an aqueous solution containing 0.93 g (0.00568mol) NaCO ₂ CH(OH)SO ₂ Na to the kettle, and pump the initial TFE/P mixed monomer with a molar ratio of 80/20 into the kettle When the internal pressure reaches 2.0MPa, polymerization starts. When the pressure in the kettle drops by 0.1MPa, pump in the supplementary TFE/P mixed monomer with a molar ratio of 50/50 until the pressure reaches 2.0MPa, and after the pressure drops by 0.1MPa again, the pump Add TFE/P mixed monomer, repeat the above mixed monomer replenishment process, when the reducing agent aqueous solution is pumped, stop the mixed monomer replenishment, polymerize until the pressure drops to 1.5MPa, remove the remaining monomer, and end the polymerization to obtain TFE-P copolymer latex; adding calcium chloride to the copolymer latex to demulsify and coagulate, and the coagulation is filtered, washed with deionized water, and dried to obtain TFE-P copolymer raw rubber.

Example 8

Add 1000 grams of deionized water, 50 grams of tert-butanol, 2.5 grams of ammonium perfluorooctanoate, and 1.46 grams (0.010 mol) of tert-amyl peroxyacetate initiator into the autoclave, seal it, fill it with nitrogen and exhaust oxygen, and stir to raise the temperature to 35 ^o C, continuously add an aqueous solution containing 0.82 grams (0.005mol) NaCO ₂ CH(OH)SO ₂ Na to the kettle, and pump the initial TFE/P mixed monomer with a molar ratio of 80/20 into the kettle until the pressure in the kettle reaches 2.0MPa, start polymerization, when the pressure in the tank drops by 0.1MPa, pump in supplementary TFE/P mixed monomer with a molar ratio of 55/45 until the pressure reaches 2.0Mp, and after the pressure drops again by 0.1MPa, pump in supplementary TFE /P mixed monomer, repeat the above mixed monomer replenishment process, when the reducing agent aqueous solution is pumped, stop the mixed monomer replenishment, polymerize until the pressure drops to 1.5MPa, remove the remaining monomer, and end the polymerization to obtain TFE-P Copolymer latex: adding calcium chloride to the copolymer latex to break the emulsion and coagulate, and the coagulation is filtered, washed with deionized water, and dried to obtain TFE-P copolymer raw rubber.

Example 9

Add 1000 grams of deionized water, 40 grams of tert-butanol, 2.0 grams of ammonium perfluorooctanoate, and 2.08 grams (0.010 mol) of tert-amyl peroxybenzoate initiator into the autoclave. ^o C, add an aqueous solution containing 1.64 grams (0.010mol) NaCO ₂ CH(OH)SO ₂ Na to the kettle at one time, pump the initial TFE/P mixed monomer with a molar ratio of 80/20 into the kettle to the pressure in the kettle When the pressure reaches 2.0MPa, start polymerization. When the pressure in the kettle drops by 0.1MPa, pump in supplementary TFE/P mixed monomer with a molar ratio of 60/40 until the pressure reaches 2.0MPa, and after the pressure drops again by 0.1MPa, pump in supplementary TFE/P mixed monomer, repeat the above mixed monomer replenishment process, when the monomer replenishment reaches 30 times, end the mixed monomer replenishment, polymerize until the pressure drops to 1.5MPa, remove the remaining monomer, end the polymerization, and obtain TFE- P copolymer latex; add calcium chloride to the copolymer latex to demulsify and coagulate, and the coagulate is filtered, washed with deionized water, and dried to obtain TFE-P copolymer raw rubber.

Example 10

Add 1000 grams of deionized water, 40 grams of tert-butanol, 1.8 grams of ammonium perfluorooctanoate, and 1.94 grams (0.010 mol) of tert-butyl peroxybenzoate initiator into the autoclave. ^o C, add an aqueous solution containing 1.64 grams (0.010mol) NaCO ₂ CH(OH)SO ₂ Na to the kettle at one time, pump the initial TFE/P mixed monomer with a molar ratio of 80/20 into the kettle to the pressure in the kettle When the pressure reaches 2.0MPa, start to polymerize. When the pressure in the kettle drops by 0.1MPa, pump in supplementary TFE/P mixed monomer with a molar ratio of 50/50 until the pressure reaches 2.0MPa, and after the pressure drops again by 0.1MPa, pump in supplementary TFE/P mixed monomer, repeat the above mixed monomer replenishment process, when the monomer replenishment reaches 25 times, end the mixed monomer replenishment, polymerize until the pressure drops to 1.5MPa, remove the remaining monomer, end the polymerization, and obtain TFE- P copolymer latex; add calcium chloride to the copolymer latex to demulsify and coagulate, and the coagulate is filtered, washed with deionized water, and dried to obtain TFE-P copolymer raw rubber.

Example 11

Add 1000 grams of deionized water, 40 grams of tert-butanol, 2.0 grams of ammonium perfluorooctanoate, and 2.08 grams (0.010 mol) of tert-amyl peroxybenzoate initiator into the autoclave. After sealing it with nitrogen and exhausting oxygen, stir and heat up to 32 ^o C, add an aqueous solution containing 1.64 grams (0.010mol) NaCO ₂ CH(OH)SO ₂ Na to the kettle at one time, pump the initial TFE/P mixed monomer with a molar ratio of 75/25 into the kettle to the pressure in the kettle When the pressure reaches 1.8MPa, start to polymerize. When the pressure in the kettle drops by 0.1MPa, pump in supplementary TFE/P mixed monomer with a molar ratio of 55/45 until the pressure reaches 1.8MPa, and after the pressure drops again by 0.1MPa, pump in supplementary TFE/P mixed monomer, repeat the above mixed monomer replenishment process, when the monomer replenishment reaches 30 times, end the mixed monomer replenishment, polymerize until the pressure drops to 1.3MPa, remove the remaining monomer, end the polymerization, and obtain TFE- P copolymer latex: add sodium chloride to the copolymer latex to demulsify and coagulate, and the coagulate is filtered, washed with deionized water, and dried to obtain TFE-P copolymer raw rubber.

Example 12

Add 1000 grams of deionized water, 40 grams of tert-butanol, 2.0 grams of ammonium perfluorooctanoate, and 2.08 grams (0.010 mol) of tert-amyl peroxybenzoate initiator into the autoclave. ^o C, add an aqueous solution containing 1.64 grams (0.010mol) NaCO ₂ CH(OH)SO ₂ Na to the kettle at one time, pump the initial TFE/P mixed monomer with a molar ratio of 80/20 into the kettle to the pressure in the kettle When the pressure reaches 1.5MPa, start to polymerize. When the pressure in the kettle drops by 0.1MPa, pump in supplementary TFE/P mixed monomer with a molar ratio of 55/45 until the pressure reaches 1.5MPa, and after the pressure drops again by 0.1MPa, pump in supplementary TFE/P mixed monomer, repeat the above mixed monomer replenishment process, when the monomer replenishment reaches 30 times, end the mixed monomer replenishment, polymerize until the pressure drops to 1.0MPa, remove the remaining monomer, end the polymerization, and obtain TFE- P copolymer latex: adding sodium sulfate to the copolymer latex to break the emulsion and coagulate, and the coagulation is filtered, washed with deionized water, and dried to obtain TFE-P copolymer raw rubber.

Claims (3)

1. the synthetic method of a tetrafluoroethylene propylene copolymer rubber, it is characterized in that: 1000 grams of deionized waters, the 20-100 gram trimethyl carbinol, 1.5 ~ 5.0 grams of ammonium perfluorocaprylates, 0.5 ~ 2.5 gram of peroxide initiator are added in autoclave, after nitrogen deoxygenation is filled in sealing, stir and be warming up to 20 ~ 40 ^oc, once or continuously adding in still with initiator mol ratio is the NaCO of 2/1 ~ 1/2 ₂cH (OH) SO ₂the Na aqueous solution, pump in still simultaneously mol ratio be 80/20 ~ 70/30 initial tetrafluoroethylene/propylene mix monomer to still internal pressure reach set(ting)value between 1.5 ~ 2.5MPa, start polymerization, when after still internal pressure decline 0.1MPa, pump into mol ratio be 60/40 ~ 50/50 supplementary tetrafluoroethylene/propylene mix monomer reach set(ting)value to pressure, and after pressure again decline 0.1MPa, pump into supplementary tetrafluoroethylene/propylene mix monomer, repeat above mix monomer and supplement process, to supplement or after reductive agent dropwises when reaching 20 ~ 30 monomers, terminate mix monomer to add, after being polymerized to pressure drop 0.5MPa, get rid of residual monomer, terminate polymerization, obtain tetrafluoroethylene propylene copolymer latex, in tetrafluoroethylene propylene copolymer latex, add flocculation agent makes latex breakdown of emulsion condense, and condensation product after filtration, deionized water wash, drying obtain tetrafluoroethylene propylene copolymer rubber.

2. the synthetic method of a kind of tetrafluoroethylene propylene copolymer rubber according to claim 1, it is characterized in that described peroxide initiator is peroxidized t-butyl perbenzoate, peroxide acid tert-amyl acetate, peroxidation tert-butyl acetate, peroxidation acetic acid tert-pentyl ester, peroxidation 3,5,5-trimethylhexanoate, peroxidation 3,5,5-tri-methyl hexanoic acid tert-pentyl ester, tert-butylperoxy isopropyl carbonate, the peroxidation 2-ethylhexyl carbonate tert-butyl ester or peroxidation 2-ethylhexyl carbonate tert-pentyl ester.

3. the synthetic method of a kind of tetrafluoroethylene propylene copolymer rubber according to claim 1, is characterized in that described flocculation agent is sodium-chlor, calcium chloride, magnesium chloride, aluminum chloride, sodium sulfate or Tai-Ace S 150.